Electrophotographic imaging devices, such as electrophotographic printers and copiers, use replaceable assemblies such as cartridges. These cartridges include components that require periodic replacement resulting from wear and materials consumed during the imaging operation. Components experiencing wear include photoconductors and charge rollers used in the electrophotographic imaging device. Components that are consumed include toner. Alternatively, electrophotographic imaging devices, such as copiers, may not use cartridges to contain the components that require periodic replacement. For these types of electrophotographic imaging devices, replacement of the components experiencing wear is generally more difficult.
Ideally, the components in the cartridge would not fail while sufficient toner remains for performing imaging operations. However, under certain conditions, components in the cartridge can fail before the toner in the cartridge is consumed. A need exists for a way to predict the possibility of failure of these components resulting from operation under these conditions.